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review.trustedfirmware.org / rust-spmc / arm-ffa / f4fc7ee1d4d60031deaba0c415982357936ece10
commitf4fc7ee1d4d60031deaba0c415982357936ece10[log] [tgz]
authorBalint Dobszay <balint.dobszay@arm.com>Mon Jun 16 15:03:55 2025 +0200
committerBalint Dobszay <balint.dobszay@arm.com>Mon Jun 16 16:13:52 2025 +0200
tree9933d00cdd9da29a4d5de08ce8d66c6928eb5ab4
parent68389c7661a9558d3c431559a3e1d89c22959861 [diff]
Fix page count handling in FFA_MEM_PERM_GET

FF-A v1.2 and lower doesn't support passing a page count argument in the
FFA_MEM_PERM_GET interface. The corresponding register value MBZ, but
the actual number of pages affected by the call is always 1. Starting
from FF-A v1.3 an arbitrary page count is allowed, but to keep backwards
compatibility the actual register value is offset by -1. Add this logic
to the Interface type.

Signed-off-by: Balint Dobszay <balint.dobszay@arm.com>
Change-Id: Ia4539210544e34016472bf7b069cc20bcd761151
1 file changed
tree: 9933d00cdd9da29a4d5de08ce8d66c6928eb5ab4
  1. .vscode/
  2. src/
  3. .gitignore
  4. Cargo.lock
  5. Cargo.toml
  6. CHANGELOG.md
  7. dco.txt
  8. LICENSE-APACHE
  9. LICENSE-MIT
  10. README.md
README.md

Arm Firmware Framework for Arm A-profile (FF-A) support library

Arm Firmware Framework for Arm A-profile (FF-A) specification

FF-A Memory Management Protocol specification

Library for handling common FF-A related functionality, create and parse interfaces and descriptors defined by FF-A. Starting from FF-A v1.2 the memory management related parts of the specification have been moved to a separate document (link above).

Design goals

  • Keep the code exception level agnostic by default. If exception level specific parts are inevitable, make it optional via a feature flag.
  • Keep the code no_std compatible. Use only core by default, make parts using alloc optional via a feature flag.
  • The interface towards the library's users should be ergonomic Rust and following Rust best-practices where possible.
    • Incorrect usage of this library when creating/packing/serializing data structures provided by this library is seen as a programmer error and the library will panic.
    • Parsing/unpacking/deserializing data structures provided by this library from a buffer is seen as runtime "user input data", and the library should make all necessary checks to validate the data. In this case the library should never panic, but return rich error types (preferably use thiserror) so the library user knows what's wrong.
  • The FF-A descriptors, packed structs and bit shifting magic should be private for the library, never exposed to the library user (i.e. ffa_v1_1 and later modules).
    • The implementation of such data structures should strictly follow the FF-A specification.
    • Preferably write a doc comment for each such definition that specifies where it comes from in the spec (i.e. Table x.y or chapter x.y.z)
    • The data structures should derive the necessary zerocopy traits.

FF-A version handling

The FF-A specification allows different components of a system to use different versions of the specification. The version used at a specific FF-A instance (i.e. an interface between two FF-A components) is discovered at runtime, either by parsing FF-A manifests or using FFA_VERSION. An FF-A component might have to use multiple versions at runtime on its different interfaces, therefore this library must be able to support this and having a compile time fixed version is not possible. Because of this, most of the functions to create or parse FF-A messages and data structures require passing the FF-A version used at the instance where the serialized data was received from or will be sent to.

Implemented features

  • Supports converting FF-A interface types between Rust types and the FF-A register ABI.
  • Memory transaction descriptor handling for FFA_MEM_* interfaces (partial).
  • FF-A v1.1+ boot information protocol.
  • FF-A partiton information descriptor.

Future plans

  • Implement missing features from FF-A v1.1 and later. Implementing FF-A v1.0 features that are deprecated by v1.1 are low priority for now.
  • Increase test coverage.
  • Create more detailed documentation to capture which parts of FF-A are currently supported.

License

The project is MIT and Apache-2.0 dual licensed, see LICENSE-APACHE and LICENSE-MIT.

Maintainers

arm-ffa is a trustedfirmware.org maintained project. All contributions are ultimately merged by the maintainers listed below.

Contributing

Please follow the directions of the Trusted Firmware Processes

Contributions are handled through review.trustedfirmware.org.

Reporting Security Issues

Please follow the directions of the Trusted Firmware Security Center

Copyright 2025 Arm Limited and/or its affiliates open-source-office@arm.com

Arm is a registered trademark of Arm Limited (or its subsidiaries or affiliates).